This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. ABSTRACT This study will establish the largest comprehensive longitudinal assessment of individuals with Duchenne muscular dystrophy, and it will be the first that uses the World Health Organization''s new framework on the International Classification of Functioning, Health and Disability. It will also longitudinally assess the psychosocial impact of the disease as it progresses on the affected persons with DMD and their families. The study will longitudinally examine the relationship between impairment, secondary conditions, activity limitation, participation and quality of life. In addition the study will evaluate the psychosocial impact of DMD in a large cohort of subjects. Regression analyses will determine the modifying effects of impairment, activities, participation and demographic data on quality of life. Successful development of an extensive and broad database will allow the performance of longitudinal prospective rehabilitation research, and evaluation of broad interventions in relation to quality of life outcomes in neuromuscular disorders. Also, the study will investigate single nucleotide polymorphisms (SNPs) in DMD patients to see how genetic variability potentially influences the efficacy of corticosteroid treatment in DMD. In addition, this project will provide a model for future multicenter efforts focusing on rehabilitation research for other neuromuscular diseases. Outcomes of this work will reach males with DMD and their families and may impact future public health policies that will positively affect their quality of life.